Field of the Invention
The present invention relates to a method of forming a through-substrate.
Description of the Related Art
As a processing method of forming a through-hole in a substrate, reactive ion etching that is a type of dry etching is widely used. The reactive ion etching introduces reactive gas into a processing chamber to generate plasma, and etches a treatment surface of a substrate using the plasma reactive gas, thereby forming a through-hole having a predetermined shape. More specifically, first, the substrate is fixed on a lower electrode in a processing chamber using an electrostatic chuck. A high-frequency power source is connected across the lower electrode and an upper electrode. The reactive gas is supplied through micropores in the upper electrode. The supplied reactive gas becomes plasma between the upper electrode and the lower electrode. Ions and radicals in the plasma are accelerated in a direction toward the substrate, and collide with the substrate, thereby allowing the substrate to be etched. At this time, if an etching mask is formed on the substrate, an area on the substrate where the etching mask is formed is not etched, and only an area where the substrate is exposed to the surface is etched.
U.S. Pat. No. 7,837,887 discloses a method of forming an ink supply port in an inkjet recording head using reactive ion etching. This method forms a first trench on a first surface of a silicon substrate. The first trench is then filled with photoresist. Subsequently, a second trench communicating with the first trench is formed from a second surface opposite to the first surface toward the first surface. This method removes the filled photoresist using oxygen plasma etching.